What Motivates Start-up Firms When Innovations are Sequential?

This paper presents a dynamic analysis of the interaction between incumbent firms and successful new entrepreneurs, that can provide R&D incentives when innovations are cumulative/sequential. It is argued that the insights of the basic model extend to varⅠ. Introduction 　Ⅱ. Preliminary: A Single-Innovation Model 　Ⅲ. A Sequential Model 　　1. The Case of R&D When z = 0 　　2. The Case of No R&D When z = 0 　Ⅳ. The R&D Motives of Startup Firms 　　1. Multiple Startups in R&D Race 　　

Analysis for the pulse-jet cleaning flow of a hot gas ceramic-filter element

학위논문(석사) - 한국과학기술원 : 기계공학과, 1998.2, [ v, 49 p. ]한국과학기술원 : 기계공학과

적분 경계층 방법에 근거한 새로운 진행 방정식을 이용한 얇은 액막 유동 해석

학위논문(박사) - 한국과학기술원 : 기계공학전공, 2008.2, [ xi, 91 p. ]New evolution equations are derived, based on application of the K??rm??n-Polhausen integral method and the imposition of a velocity profile accounting for inertial effects, rather than the usual parabolic profile, for the analysis of thin liquid film flows with/without condensation. First, the validity and accuracy of the equations without condensation are demonstrated via both a linear and nonlinear stability analysis for the case of flow down an inclined plane, and the solutions obtained are seen to be an improvement over earlier results. In addition, the evolution equations are used to model the case of a thin liquid film flowing down an inclined plane containing a well defined trench topography, with the predicted film profile for Reynolds number greater than zero shown to be in excellent agreement with a recent corresponding finite element solution of the full Navier-Stokes equations taken from the literature. Using a similar procedure, a new form of the condensation rate is derived from the energy equation using a temperature profile accounting for energy convection effects. From this condensation rate as well as the evolution equations including condensation effect, convenient formulae for the film thickness and the heat transfer rate as a function of Jacob and Prandtl numbers are derived for the laminar condensate film condensation on a vertical plate. The results are in good agreement with the previous similarity solutions of the boundary layer equations. The validity and accuracy of the present approach is also demonstrated via the linear stability analysis of vertical condensate film flow. Finally, the evolution equations are used to model the condensate film flow over topography. The result is seen to follow the analytic solution derived in the present analysis when the inflow and outflow boundaries are approached and has a wave profile similar to that of an isothermal flow case near the topographic region.한국과학기술원 : 기계공학전공

Influence of Cu Composition on the Mechanical Properties and Microstructure of Ti-Al-Si-Cu-N thick films

Quinary component of 3μm thick Ti-Al-Si-Cu-N films were deposited onto WC-Co and Si wafer substrates by using an arc ion plating(AIP) system. In this study, the influence of copper(Cu) contents on the mechanical properties and microstructure of the films were investigated. The hardness of the films with 3.1 at.% Cu addition exhibited the hardness value of above 42 GPa due to the microstructural change as well as the solid-solution hardening. The instrumental analyses revealed that the deposited film with Cu content of 3.1 at.% was a nano-composites with nano-sized crystallites (5–7 nm in dia.) and a thin layer of amorphous Si3N4 phase